SMaRT-PCR: Sampling with Mask and Reverse Transcriptase PCR, a promising non-invasive diagnostic tool for paediatric pulmonary tuberculosis

Purpose Diagnostic challenges in pediatric TB, like difficulties obtaining sputum, need for invasive sampling, and suboptimal sensitivity of existing detection tools, advocate for sputum-free, child-friendly, and diagnostically accurate methods. This proof-of-concept study evaluates the diagnostic potential of non-invasively s ampling patient bioaerosols using a mask combined with reverse transcriptase (RT)PCR (SMaRT-PCR) for pediatric TB detection. Methods In this case-control study, we recruited 51 children (30 confirmed TB and 21 without TB) aged 2-15. Exhaled bioaerosols were captured on gelatin membrane-layered N-95 masks in a 10-minute process that involved talking, coughing, and breathing. Two mask samples were consecutively collected from children with TB and tested using GeneXpert and in-house RT-PCR for 16s and rpoB RNA. The control cohort underwent single mask sampling and testing with RT-PCR. Mask sampling acceptability was assessed using a questionnaire and a Likert-scale. Results The sensitivity and specificity of SMaRT-PCR for detecting 16s and rpoB among 24 treatment naïve patients were 75% and 95%, respectively, comparable to GeneXpert testing in standard samples from the same patients. Mask sampling with GeneXpert had sensitivity of only 13%. Over 90% of children were comfortable with mask sampling, and > 80% were happy or very happy on the Likert scale with the procedure. Conclusion This is the first study to provide evidence for testing patient bioaerosols as a promising alternative for detecting pediatric TB. SMaRT-PCR has potential in a hub-and-spoke model, where samples collected from remote locations can be centrally tested by RT-PCR at district-level laboratories, enabling equitable access to diagnostic care. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This research study was supported through private donation to FMR from Mr. Nadir Godrej (Indian Industrialist) and FMR institutional funds. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was undertaken after the approval of the Institutional Research Ethics Committees of The Foundation for Medical Research (FMR/IREC/TB/02/2019), Bai Jerbai Wadia Hospital for Children (IEC/BJWHC/97/2019), and JJ Hospital (IEC/Pharm/RP/313/Feb-2020) I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The data supporting this study's findings are available from the corresponding author upon reasonable request.